Jotaro Kidou operates under the alias Blaster Kid as a core member of the mercenary group Cosmo Ranger J9. His recruitment was orchestrated by Isaac Godonov, who united him with Steven Bowie and Machiko Valencia to combat criminal organizations across the colonized solar system.

As J9's designated sniper and gunslinger, he fulfills a critical tactical role. His personality reflects the team's choleric temperament, often displaying fierce concentration during operations. He is characterized by his signature phrase "Yay," serving as both a rallying cry and a gesture of unity among J9 members.

Within the Braiger robot combat system, he typically operates weapon systems during synchronized attacks, utilizing specialized armaments like the Cosmo Winders against criminal factions.

The series' narrative structure begins with episodic missions that gradually develop the core characters. While specific details of his personal backstory or evolution remain limited, his role as a combat specialist within the J9 framework is consistently defined. Information regarding his depiction in expanded media is unavailable in the provided sources.